The PEC performance of BiVO4 was enhanced by preparing the CoFeBi/BiVO4 photoanode using an ultrafast photoassisted electrodeposition method

Abstract

BiVO₄ is a promising material for water oxidation due to its suitable physical and chemical properties. However, the BiVO₄ film has limitations such as poor electron transport, surface charge recombination, and low catalytic activity, which affect its performance. To address these issues, under light assistance (AM 1.5G), we employed a simple electrodeposition method to selectively react the film for only 10 seconds in a 1 M potassium borate electrolyte (pH = 9.5) containing iron and cobalt sources. This method allowed for the fast loading of bimetallic borate compounds onto the vanadium–bismuth oxide photoanode, resulting in efficient photoelectrochemical (PEC) water splitting. The modification of the BiVO₄ electrode through this process reduces the electron–hole composite rate, thereby improving PEC performance, photocurrent, and oxygen release. The CoFeB_i/BiVO₄ photoanode demonstrated a significant photocurrent density of 4.4 mA cm⁻² at 1.23 V vs. RHE, which is approximately 2.6 times higher than that of BiVO₄. This improvement can be attributed primarily to the synergistic effect of the cobalt–iron-based cocatalyst, which exhibits outstanding water oxidation activity through its Fe³⁺ and Co²⁺ active sites. This work introduces a new research pathway for applications in photovoltaics and photoelectrochemical water splitting.